Low emission fluid transfer device

ABSTRACT

A fluid transfer system includes a transfer device coupled to a dry break coupler. The transfer device includes a valve assembly moveable between an open and a closed position. The valve assembly includes a main valve and a pilot valve. An actuator controls both the main valve and the pilot valve. A cam plate interconnects the actuator and the valve assembly. The cam plate provides a quick acting shutoff to quickly move the valve assembly to the closed position. A pivotal and rotatable connector couples the transfer device to the dry break coupler. A lock is integrated with the actuator to lock the valve assembly in the closed position.

FIELD OF THE INVENTION

The present invention generally relates to fluid transfer systems forproviding fluid communication between a fluid source and a fluiddestination. More specifically, the present invention relates to a fluidtransfer system including a transfer device and a dry break coupler thatreleasably join together to link the fluid source and the fluiddestination.

BACKGROUND OF THE INVENTION

Fluid transfer systems are generally used for transferring fluid, e.g.,gas or liquid, from a fluid source, e.g., a delivery truck, to a fluiddestination, e.g., a storage tank. These fluid transfer systems oftenuse conventional valve assemblies and conduits to communicate and managefluid flow. Typically, a transfer device includes a valve assembly thatopens to release the flow of fluid from the delivery truck. The storagetank often includes a receiver or connector to which the transfer deviceis releasably coupled. Once the transfer device is mounted to thereceiver on the storage tank, the valve assembly is opened and fluidmoves from the delivery truck to the storage tank.

When the delivery is complete, the transfer device is de-coupled fromthe receiver. As this occurs, fluid often escapes or vaporizes into theatmosphere due to the volume of space inside the transfer device thatopens to atmosphere and the volume of space inside the receiver thatopens to atmosphere. This waste can be costly when added across hundredsto thousands of deliveries. Emissions from some fluids can also behazardous or damaging to the environment. In addition to the emissionsassociated with de-coupling the transfer device and receiver,inadvertent emissions can also occur by accidentally opening the valveassembly prior to being ready for transfer.

Many prior art transfer devices use levers or hand wheels for openingand closing valve assemblies to manage the fluid flow between the fluidsource and the fluid destination. Some levers or hand wheels require anexcessive amount of torque to close the valve assembly and stop fluidflow during an inadvertent emission. Some levers or actuators alsorequire a high degree of rotation, e.g., 90 degrees of rotation or more,to close the valve assemblies. The extra effort and time to close thevalve assemblies can result in large amounts of unnecessary fluidemissions.

The interconnection of the transfer device and the receiver in prior artsystems can often be difficult for an operator. For example, thetransfer device typically must be elevated and lined up accurately tothe receiver to couple the two together. The equipment is normally veryheavy for an operator to carry and couple to the receiversimultaneously. In this situation, it is desired to provide an effectivecoupling technique to avoid any body strain to the operator fromcarrying and installing the equipment.

Therefore, there is a need in the art to provide a fluid transfer systemthat controls fluid communication in a way that helps reduce fluidemissions. Furthermore, there is a need in the art to provide a transferdevice that is more maneuverable and easy to operate.

SUMMARY OF THE INVENTION AND ADVANTAGES

The present invention provides a transfer device for transferring fluid.The transfer device includes a housing defining a bore. An actuator iscoupled to the housing for movement relative to the housing. A valveassembly is disposed in the bore and is moveable between an openposition and a closed position. The valve assembly includes a main valvemoveable between an open-main valve position and a closed-main valveposition and a pilot valve moveable between an open-pilot valve positionand a closed-pilot valve position. The actuator is operatively coupledto the valve assembly such that the pilot valve and the main valve areeach moveable in response to the movement of the actuator with the pilotvalve reaching the open-pilot valve position before the main valvereaches the open-main valve position.

The pilot valve feature allows the actuator to move the main valvewithout requiring much force when the transfer device is mounted to asuitable receiver, but makes it difficult to open the main valve whenthe transfer device is disconnected from the receiver. For example, inone aspect of the invention, when the transfer device is mounted to thereceiver and the pilot valve is moved to the open-pilot valve position,fluid is allowed to pressurize in front of and behind the main valve.This makes it easy to move the main valve to the open-main valveposition and establish fluid communication. Conversely, when thetransfer device is disconnected from the receiver, pressure of the fluidbehind the main valve urges it into the closed position. It's not untilthe main valve is coupled to the receiver and pressure can be equalizedin front of and behind the main valve that the operator can easily openthe main valve. Pressures of about 25 to about 200 psi are oftenencountered, such as in liquid propane (LP) transfer.

The present invention also provides a transfer device comprising ahousing defining a bore. A valve assembly is disposed in the bore andmoveable between an open position and a closed position. An actuator ispivotally coupled to the housing for pivotal movement about a pivot axisto move the valve assembly between the open position and the closedposition. A cam plate is disposed in the bore of the housing andinterconnects the valve assembly and the actuator. The cam plate definesa cam profile having first and second distinct locations. The actuatorengages the first location of the cam profile when the valve assembly isin the closed position and engages the second location of the camprofile when the valve assembly is in the open position. The actuatormoves from the first location to the second location along the camprofile to move the cam plate thereby moving the valve assembly betweenthe open and closed positions.

The cam plate provides a quick acting shut-off. The cam plateconfiguration allows the operator to bump the actuator and rotate theactuator only a fraction of a rotation to move the valve assembly to theclosed position in a quick manner. This can be extremely useful in caseswhere leaks occur and fluid communication must be stopped immediately toavoid fluid loss.

The present invention further provides a transfer device for coupling toa receiver. The transfer device comprises a housing defining a borehaving a first end and a second end disposed along a longitudinal axis.The housing further defines a first race having a first width adjacentthe second end. A valve assembly is disposed in the bore and moveablebetween open and closed positions. An actuator is coupled to the valveassembly for moving the valve assembly between the open and closedpositions. A connector is coupled to the housing about the second endand defines a second race having a second width. A plurality of bearingmembers are disposed between the first race and the second race forallowing rotational movement of the connector relative to the housingabout the longitudinal axis. The connector pivots between differentangular positions relative to the longitudinal axis to ease mounting ofthe transfer device to the receiver.

Thus, the connector can both swivel (or rotate) and pivot. The swivelingand pivoting motion provides assistance to couple the transfer device tothe receiver. Typically, the transfer device needs to be alignedaccurately with the receiver for coupling the two together. Due to theweight of the transfer device, which is formed primarily of metalcomponents, this can often be difficult to achieve. With a pivoting andswiveling connector coupled to the housing, the transfer device does notneed to be aligned perfectly with the receiver, making installationeasier.

The present invention still further provides a transfer device fortransferring fluid. The device comprises a housing defining a bore. Avalve assembly is disposed in the bore and moves between an openposition and a closed position. An actuator is pivotally coupled to thehousing for pivotal movement about a pivot axis to move the valveassembly between the open position and the closed position. A lock iscoupled to the actuator and moves between a locked position and anunlocked position. The housing defines at least one catch such that thelock is engaged in the catch when the valve assembly is in the closedposition preventing the pivotal movement about the pivot axis and thelock is disengaged from the at least one catch when the lock is movedfrom the at least one catch allowing the pivotal movement about thepivot axis to move the valve assembly to the open position.

The lock secures the actuator to the housing to hold the valve assemblyin the closed position. The lock further reduces any accidental movementto move the valve assembly to the open position, avoiding inadvertentloss of fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages of the present invention will be readily appreciated asthe same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is a perspective view of a fluid transfer system illustrating atransfer device and a dry break coupler;

FIG. 2 is a cross-sectional view of the transfer device illustrating amain valve in a closed-main valve position and a pilot valve in aclosed-pilot valve position;

FIG. 2A is an exploded cross-sectional view of the main valve and thepilot valve illustrated in FIG. 2;

FIG. 3 is a cross-sectional view of the transfer device illustrating themain valve in the closed-main valve position and the pilot valve in anopen-pilot valve position;

FIG. 3A is an exploded cross-sectional view of the main valve and thepilot valve illustrated in FIG. 3;

FIG. 4 is a cross-sectional view of the transfer device illustrating themain valve in an open-main valve position and the pilot valve in theopen-pilot valve position;

FIG. 5 is a perspective assembly view of the main valve, the pilotvalve, and a cam plate;

FIG. 6 is a cross-sectional view of the transfer device taken generallyalong the line 6-6 in FIG. 2;

FIG. 7 is a side view of an actuator with a lock illustrating the lockin a locked position;

FIG. 8 is an exploded perspective view of the transfer device;

FIG. 9 is a cross-sectional view of a connecting nut, coupling element,and ball bearing configuration in one position;

FIG. 9A is a cross-sectional view of the connecting nut, couplingelement, and ball bearing configuration in another position;

FIG. 10 is a cross-sectional view of the transfer device coupled to thedry break coupler illustrating the main valve in the closed-main valveposition, the pilot valve in the closed-pilot valve position, and acoupler valve in a closed-coupler valve position; and

FIG. 11 is a cross-sectional view of the transfer device coupled to thedry break coupler illustrating the main valve in the closed-main valveposition, the pilot valve in the open-pilot valve position, and thecoupler valve in the closed-coupler valve position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, a fluid transfersystem is generally shown at 20. Referring to FIG. 1, the fluid transfersystem includes a transfer device 22 and a dry break coupler 24.Generally, the transfer device 22 is coupled to a conduit (not shown)attached to a fluid source. The dry break coupler 24 is generallycoupled to a conduit (not shown) attached to a fluid destination such asa storage tank. The transfer device 22 is configured to releasablyconnect to the dry break coupler 24 to provide fluid communicationbetween the fluid source and the fluid destination. The fluid travelsfrom the fluid source to the fluid destination under a fluid pressure.The fluid can include liquid or gas. The present invention isparticularly adapted for transferring liquid propane, but is notintended to be so limited.

Referring to FIGS. 2 and 2A, the transfer device includes a housing 26that defines a bore 28 having an inlet 30 and an outlet 32. The housing26 may be made of a metal or alloy, such as cast iron, steel, or anyother suitable material. The housing 26 is defined about a longitudinalaxis A. The housing 26 includes an integrated valve collar 34 forreceiving a pressure relief valve 36. The pressure relief valve 36relieves the fluid pressure in instances where the fluid pressure insidethe bore 28 of the housing 26 exceeds a predefined limit. The housing 26defines a hole for providing communication with the pressure reliefvalve 36.

A top handle 38 and a bottom handle 40 are each integrated with thehousing 26 for ease of carrying and maneuvering the transfer device 22.This is particularly useful when coupling the transfer device 22 to thedry break coupler 24 or other suitable receiver. A clip 42, generallyhaving a U-shaped configuration, is coupled to the top handle 38 forhanging the transfer device 22 during storage or use. A fastener 44couples the clip 42 to the top handle 38.

A valve assembly 46 is disposed in the bore 28 of the housing 26 and ismoveable between an open position and a closed position. An actuator 48is pivotally coupled to the housing 26 for pivotal movement about apivot axis P. The pivotal movement of the actuator 48 moves the valveassembly 46 between the open position and the closed position. Morespecifically, the actuator 48 pivots toward the outlet 32 to move thevalve assembly 46 from the closed position to the open position and theactuator 48 pivots away from the outlet 32 to move the valve assembly 46from the open position to the closed position.

The valve assembly 46 includes a main valve 50 moveable between anopen-main valve position and a closed-main valve position. The valveassembly further includes a pilot valve 52 moveable between anopen-pilot valve position and a closed-pilot valve position. The mainvalve 50 and the pilot valve 52 may be made of a metal or alloy, such asstainless steel or carbon steel or any other suitable material. Theactuator 48 is operatively coupled to the valve assembly 46. Morespecifically, the actuator 48 moves the main valve 50 and the pilotvalve 52 between their respective open positions and closed positions inresponse to the pivotal movement of the actuator 48.

Referring specifically to FIG. 2A, the main valve 50 includes a mainvalve body 53. The main valve body 53 includes a face 54 having apreferably circular shape. A sealing member 56, formed of a materialsuitable for sealing, such as a carboxylated nitrile material, iswrapped around the main valve body 53 adjacent to the face 54. When thevalve assembly 46 is in the closed position, the face 54 acts with thesealing member 56 to close the outlet 32 of the bore 28, preventing anyfluid from exiting the outlet 32. The main valve body 53 defines anaperture 58 extending completely therethough. The aperture 58 includes afirst section 60, a second section 61, and a third section 62, each ofprogressively larger diameter.

The pilot valve 52 is coupled to the main valve 50. The pilot valve 52includes a body portion 67 that is at least partially disposed withinthe third section 62 of the aperture 58. The body portion 67 has adiameter slightly smaller than a diameter of the third section 62 todefine an annular space therebetween. The pilot valve 52 furtherincludes a head portion 69 that is at least partially disposed withinthe second section 61 of the aperture 58. The head portion 69 has adiameter that is slightly smaller than a diameter of the second section61 to define an annular space therebetween. The first section 60 opensthrough the face 54 and has a diameter smaller than the head portion 69.

A sealing member 71, e.g., an o-ring seal, is disposed in the secondsection 61 about the first section 60. The sealing member 71 is made ofa material suitable for sealing, such as a nitrile material. The headportion 69 abuts the sealing member 71 to close fluid flow through theaperture 58 when the pilot valve 52 is in the closed-pilot valveposition. The head portion 69 is unseated from the sealing member 71when the pilot valve 52 moves to the open-pilot valve position. Thepilot valve 52 is moveable within the second 61 and third 62 sectionsduring the pivotal movement of the actuator 48.

A pair of retainer pins 64 are disposed in the third section 62 of theaperture 58 for coupling the pilot valve 52 to the main valve 50. Themain valve 50 defines a first opening 66 and a second opening 68 forreceiving the retainer pins 64. It is to be appreciated that theretainer pins 64 may comprise any other retainer device so as toslidably couple the pilot valve 52 to the main valve 50.

The pilot valve 52 is configured for moving or sliding a predetermineddistance in the aperture 58 relative to the main valve 50 duringactuation before engaging the main valve 50 to unseat the main valve 50from its position at the outlet 32. In particular, the pilot valve 52defines a travel path 70 for the retainer pins 64. The travel path 70 isdefined as an annular groove in the body portion 67 of the pilot valve52. The pilot valve 52 includes an abutment 74 defining one end of thetravel path 70. The abutment 74 is spaced from the retainer pins 64 whenthe pilot valve 52 is in the closed-pilot valve position. As theactuator 48 is pivoted toward the outlet 32 to move the valve assembly46 to the open position, the pilot valve 52 is initially moved to theopen-pilot valve position and the abutment 74 moves toward the retainerpins 64. The main valve 50 remains stationary. After the pilot valve 52reaches the open-pilot valve position, further pivoting of the actuator48 toward the outlet 32 abuts the abutment 74 against the retainer pins64, thus pulling the main valve 50 toward the open-main valve position.Thus, the pilot valve 52 is opened before the main valve 50 is opened.

It should be understood that the coupling of the pilot valve 52 to themain valve 50 may be configured other than that shown in the exemplaryembodiment. The retainer pins 64 and the travel path 70 is one examplein which the pilot valve 52 is moveably coupled to the main valve 50.For example, the pilot valve 52 may be designed to receive one retainerpin rather than a pair of retainer pins.

Referring now to FIGS. 2-4, a cam plate 76 is disposed in the bore 28 ofthe housing 26 between the inlet 30 and the outlet 32. The cam plate 76may be made of a metal or alloy, such as stainless steel or carbon steelor any other suitable material. The cam plate 76 is slideably coupled tothe housing 26 and interconnects the actuator 48 and the valve assembly46. More specifically, the housing defines guide grooves 77 (see alsoFIG. 6) inside the bore 28 for slideably receiving and retaining the camplate 76. The guide grooves 77 (4 total in the embodiment shown) arediametrically opposed to one another to align the cam plate 76 top tobottom. The guide grooves 77 are sized slightly larger than a width ofthe cam plate 76 to allow smooth sliding motion, but still retain thecam plate 76.

A crank assembly 78 operatively connects the actuator 48 to the camplate 76. The crank assembly 78 forms part of the actuator 48 and ismoveable about the pivot axis P when the actuator 48 is actuated. Morespecifically, the crank assembly 78 includes a crank shaft 85 (see alsoFIGS. 6 and 7) that is moveable about the pivot axis P. A crank plate 87interconnects the crank shaft 85 and a crank pin 80 to fix thesecomponents together. As the actuator 48 is rotated about the pivot axisP, the crank shaft 85 rotates about the pivot axis P, thereby moving thecrank pin 80.

The cam plate 76 is moveable by the crank assembly 78. Morespecifically, the cam plate 76 defines a slot having a cam profile 82with first 81 and second 83 distinct locations for receiving the crankpin 80 of the crank assembly 78. The crank pin 80 is moveable along thecam profile 82 among the first 81 and second 83 locations by the pivotalmovement of the actuator 48, whereby movement of the crank pin 80 alongthe cam profile 82 moves the cam plate 76 in an axial direction in thebore 28. The crank pin 80 may be made of a metal or alloy, such asstainless steel or carbon steel or any other suitable material. Acylindrical sleeve 89, preferably formed of a nylon material, covers thecrank pin 80 for reducing friction as the crank pin 80 moves along thecam profile 82. A retainer ring 91 is coupled to the crank pin 80 forretaining the cylindrical sleeve 89 to the crank pin 80.

The cam plate 76 further includes a first yoke 84 and a second yoke 86.A pin fastener 88 couples the valve assembly 46 to the second yoke 86 ofthe cam plate 76. It is to be appreciated that any other suitablefastener may be used. In particular, the pin fastener 88 axially fixesthe cam plate 76 to the pilot valve 52 such that any axial movement ofthe cam plate 76 moves the pilot valve 52. The valve assembly 46 isconnected in series to the cam plate 76 with the valve assembly 46located directly in front of the cam plate 76 toward the outlet 32 ofthe bore 28. The crank assembly 78 moves the cam plate 76 toward theinlet 30 of the bore 28 in the axial direction in response to thepivotal movement of the actuator 48 toward the outlet 32, thus pullingthe valve assembly 46 toward the inlet 30 of the bore 28 also in anaxial direction.

FIG. 2 shows the crank pin 80 engaged in the first, lower location 81 ofthe cam profile 82, wherein the main valve 50 is in the closed-mainvalve position and the pilot valve 52 is in the closed-pilot valveposition. Although difficult to see in FIG. 3, upon slight pivoting ofthe actuator 48, the crank pin 80 moves slightly in the first location81 along the cam profile 82 such that the cam plate 76 pulls the pilotvalve 52 to the open-pilot valve position. The main valve 50 remains inthe closed-main valve position. As shown in FIG. 4, further pivoting ofthe actuator 48 engages the crank pin 80 in the second, upper location83 of the cam profile 82, wherein the cam plate 76 pulls the pilot valve52 such that the abutment 74 of the travel path 70 of the pilot valve 52engages the retainer pins 64 of the main valve 50, thereby pulling themain valve 50 to the open-main valve position.

The cam profile 82 is designed to reduce the effort required to pivotthe actuator 48 away from the outlet 32 to move the valve assembly 46from the open position to the closed position, i.e., move the crank pin80 from the second location 83 to the first location 81. The cam profile82 defines a detent pocket 90 at the second location 83 to hold thecrank pin 80 in the second location 83.

A spring 92 is disposed between the inlet 30 of the bore 28 and the camplate 76 for biasing the cam plate 76 against the crank pin 80 so as tohold the crank pin 80 in the detect pocket 90 when the valve assembly 46is open. The spring 92 may be made of a metal or alloy, such asstainless steel or carbon steel or any other suitable material. Thedetent pocket 90 is designed such that the crank pin 80 is easily movedout from the detent pocket 90, while still providing enough retention tohold the crank pin 80. The force necessary to rotate the actuator 48away from the outlet 32 to move the crank pin 80 out of the detentpocket 90 is small.

Essentially, pivoting of the actuator 48 need only move the crank pin 80over a humped profile section between the second location 83 and thefirst location 81. Once the crank pin 80 is manually moved over thehumped profile by the operator, the spring force takes over and axiallypushes the cam plate 76 and valve assembly 46 to close the valveassembly. The amount of pivoting of the actuator 48 required by theoperator to move the crank pin 80 out of the detent pocket 90 is lessthan 90 degrees, more preferably less than 45 degrees, and mostpreferably less than 15 degrees.

Referring now to FIGS. 1, 6, 7 and 8, the actuator 48 generally has aU-shaped configuration, although other configurations may be utilized. Alock 94 is integrated with the actuator 48 and moveable between a lockedposition and an unlocked position. The actuator 48 includes a pair ofarms 96 for coupling the lock 94 to the actuator 48. A screw fastener100 pivotally couples each of the arms 96 to the housing 26 of thetransfer device 22. As best shown in FIG. 6, the screw fastener 100fixes one of the arms 96 to the crank shaft 85 of the crank assembly 78,thereby providing the crank assembly 78 with pivotal movement about thepivot axis P when the actuator 48 is rotated. It is to be appreciatedthat any suitable fastener may be used. A grasping rod 102 interconnectsthe arms 96 for grasping the actuator 48 to pivot the actuator 48 aboutthe pivot axis. A screw fastener 100 couples the rod 102 to the arms 96of the actuator 48. A grip 106, preferably made of a plastic material,is coupled to the rod 102 for providing comfort when grasping the rod102 to rotate the actuator 48.

The housing 26 of the transfer device 22 defines a pair of catches 108,or pockets, for receiving and engaging the lock 94 when the valveassembly 46 is in the closed position. More specifically, the lock 94includes a pair of tabs 110 for engaging the catches 108. The lock 94 isin the locked position when the tabs 110 are engaged in the catches 108,thus preventing the actuator 48 from pivoting about the pivot axis P tomove the valve assembly 46 from the closed position to the openposition. The lock 94 is in the unlocked position when the tabs 110 ofthe lock 94 are moved out from the catches 108, thus allowing theactuator 48 to pivot about the pivot axis P to move the valve assembly46 from the closed position to the open position.

A lock spring 112 is disposed in slots 113 in each of the arms 96 of theactuator 48. The lock springs 112 are coupled to the lock 94 and actbetween the arms 96 and the lock 94 such that the lock springs 112 biasthe tabs 110 of the lock 94 toward the catches 108. The lock 94 furtherincludes a lip 114 for simultaneously grasping the lock 94 with the grip106 of the actuator 48 to move the tabs 110 of the lock 94 away from thecatches 108 (see FIG. 3). It is to be appreciated that any number ofcatches 108 and tabs 110 may be used to engage and disengage the lock.

The housing 26 of the transfer device 22 further defines a pair ofcontoured recesses 116 for guiding the tabs 110 of the lock 94 duringthe pivotal movement of the actuator 48. As mentioned above, the lock 94is moveable between a locked position and an unlocked position. As thelock 94 is moved from the locked position to the unlocked position bygrasping and pulling the lip 114 of the lock 94 away from the catches108, slight pivoting of the actuator 48 engages the tabs 110 of the lock94 with the recesses 116. The recesses 116 hold the lock 94 in theunlocked position, thereby allowing the actuator 48 to fully pivot andmove the valve assembly 46 from the closed position to the openposition. The tabs 110 of the lock 94 follow the recesses 116 during thepivotal movement of the actuator 48. As the tabs 110 of the lock 94 passback over the catches 108 when the valve assembly 46 is being moved backto the closed position, the tabs 110 engage in the catches 108 withassistance from the bias of the lock springs 112.

Referring now to FIGS. 8, 9, and 9A, the components for coupling thetransfer device 22 to the dry break coupler 24 will be discussed. A nutadapter 118 forms part of the housing 26 and defines the outlet 32 ofthe bore 28. A connector is pivotally and rotatably coupled to the nutadapter 118. The connector includes a coupling element, hereinafterreferred to as a joint member 126 and a threaded collar 136 fixed to thejoint member 126. The joint member 126 is pivotally and rotatablycoupled to the nut adapter 118. The nut adapter 118 and the joint member126 may both be made of a metal or alloy, preferably 4140 high gradetool steel, or any other suitable material. The threaded collar 136 maybe made of a metal or alloy, such as brass or steel, or any othersuitable material.

The nut adapter 118 defines a first annular race 122 having a firstwidth 124. The joint member 126 defines a second annular race 128 havinga second width 130. The first race 122 is defined by a first racesurface 120 and the second race 128 is defined by a second race surface132 such that when the nut adapter 118 is coupled to the joint member126, the second race surface 132 is spaced from the first race surface120 to define a gap therebetween. A plurality of bearing members, e.g.,ball bearings 134, are disposed between the first race 122 and thesecond race 128. A bearing plug 135 is disposed in the joint member 126for plugging the ball bearings 134 and securing the ball bearings 134 inthe races 122, 128. The threaded collar 136 is configured for couplingto the dry break coupler 24. The threaded collar 136 and the jointmember 126 are rotatable about the ball bearings 134 relative to the nutadapter 118 for screwing the threaded collar 136 to the dry breakcoupler 24.

Referring specifically to FIGS. 9 and 9A, the first width 124 of thefirst race 122 is greater than the second width 130 of the second race128. The first race 122 preferably has a parabolic shape with a firstradius and a second radius. A flat middle portion 137 connects the firstradius and the second radius. The first and second radii are equal insome embodiments. The middle portion 137 preferably has a length of fromabout 0.01 inches to about 0.1 inches. More preferably, the middleportion 137 is from about 0.05 inches to about 0.07 inches. Mostpreferably, the middle portion 137 is about 0.06 inches. The second race128 has a circular shape with a uniform radius matching the shape of theball bearings 134. The configuration of the nut adapter 118, the jointmember 126 and the races 122, 128 allows for a pivoting motion of thethreaded collar 136 relative to the nut adapter 118. In particular, thethreaded collar 136 is capable of pivoting between a plurality ofangular positions relative to the longitudinal axis A (see FIG. 9A). Thepivoting motion eases installation when coupling the transfer device 22to the dry break coupler 24.

Referring now to FIGS. 10-11, the dry break coupler 24 includes acoupler housing 138 defining a coupler bore 140. The coupler bore 140includes a coupler inlet 142 and a coupler outlet 144. The coupler inlet142 receives the transfer device 22 for fluid communication between thefluid source and the fluid destination. A coupler valve 146 is disposedin the coupler bore 140 and is moveable between an open-coupler valveposition and a closed-coupler valve position. The coupler valve 146includes a valve face 148 of a circular shape. The coupler valve 146abuts the coupler inlet 142 of the coupler bore 140 when the couplervalve 146 is in the closed-coupler valve position.

A coupler seal 150, preferably formed of a material suitable forsealing, such as an elastomeric material, is wrapped around the couplervalve 146 to prevent the fluid from leaking out of the dry break coupler24 when the coupler valve 146 is in the closed-coupler valve position. Acoupler spring 152 continuously biases the coupler valve 146 in theclosed-coupler valve position. The coupler valve 146 includes a guiderod 147. A guide mount 149 is fixed to the coupler housing 138 andslidably receives the guide rod 147 as the coupler valve 146 movesbetween its open and closed positions. The dry break coupler 24 furtherincludes a pressure relief valve 154 (see FIG. 1) for relieving thefluid in instances where the pressure inside the coupler bore 140exceeds a predefined limit.

The operation of the fluid transfer system will now be discussed. FIG.10 shows the transfer device 22 coupled to the dry break coupler 24 withthe valve assembly 46 of the transfer device 22 in the closed positionand the coupler valve 146 of the dry break coupler 24 in the closedposition. The configuration minimizes a space between the face 54 of themain valve 50 and the coupler valve face 148. The minimized spacereduces fluid emissions upon disconnecting the transfer device 22 fromthe dry break coupler 24. The minimized space is achieved due to theproximity of the main valve 50 to the outlet 32 and the proximity of thecoupler valve 146 to the coupler inlet 142.

Once the transfer device 22 is securely coupled to the dry break coupler24, the actuator 48 is pivoted toward the outlet 32, thereby moving thecrank pin 80 along the cam profile 82 of the cam plate 76. The crank pin80 follows the cam profile 82 and moves the cam plate 76 slightly in thefirst location, thereby moving the pilot valve 52 from the closed-pilotvalve position to the open-pilot valve position. With the pilot valve 52in the open-pilot valve position, the fluid is allowed to flow from thebore 28 of the transfer device 22 through the aperture 58 and into thespace between the face 54 of the main valve 50 and the coupler valveface 148.

More specifically, as the pilot valve 52 is moved to the open-pilotvalve position, the fluid flows through the third section 62 and thesecond section 61 of the aperture 58 of the main valve 50, in theannular spaces between the pilot valve 52 and the main valve body 53,and then through the first section 60 of the aperture 58, whereby thefluid enters the space between the face 54 of the main valve 50 and thecoupler valve face 148 (see the illustration of FIG. 3A). It should beappreciated that the retainer pins 64 and the travel path 70 of thepilot valve 52 are configured such that the fluid flow will not beblocked, i.e., the configuration does not act as a seal. This is alsotrue when the abutment 74 engages the retaining pins 64.

The pilot valve 52 allows the fluid pressure to equalize in the bore 28of the housing 26 of the transfer device 22 and in the space between theface 54 of the main valve 50 and the coupler valve face 148. In otherwords, the pressure of the fluid is equal in front of and behind themain valve 50. As a result, the effort required to pivot the actuator 48and move the main valve 50 from the closed-main valve position to theopen main-valve position is substantially reduced. Without this pressureequalization, the operator would have to act against the fullypressurized force of the fluid acting behind the main valve 50 to openthe main valve 50. This feature reduces any inadvertent pivoting of theactuator 48 and opening of the main valve 50. For example, when thetransfer device 22 is disconnected from the receiver, pressure of thefluid behind the main valve 50 is at the fluid pressure (which can be upto about 375 psi in the case of liquid propane), while pressure in frontof the main valve 50 is at atmosphere. It's not until the main valve 50is coupled to the receiver and pressure can be equalized in front of andbehind the main valve 50 that the operator can easily open the mainvalve.

When the main valve 50 reaches the open-main valve position, the fluidexits the bore 28 through the outlet 32 applying a force to the couplervalve face 148. The force moves the coupler valve 146 from theclosed-coupler valve position to the open-coupler valve position, andenters the coupler bore 140 of the dry break coupler 24, therebyallowing fluid transfer from the fluid source to the fluid destination.To stop fluid communication between the fluid source and the fluiddestination, the actuator 48 is pivoted to move the valve assembly 46from the open position to the closed position as previously described.

The present invention has been described herein in an illustrativemanner, and it is to be understood that the terminology which has beenused is intended to be in the nature of words of description rather thanof limitation. Obviously, many modifications and variations of thepresent invention are possible in light of the above teachings. Theinvention may be practiced otherwise than as specifically describedwithin the scope of the appended claims.

What is claimed is:
 1. A transfer device for transferring fluid, saiddevice comprising: a housing defining an inlet, an outlet, and alongitudinal axis; an actuator pivotally coupled to said housing about apivot axis transverse to said longitudinal axis, said actuator having agrasping portion moveable fore and aft relative to said housing to pivotsaid actuator about said pivot axis; a lock operatively coupled to saidactuator and movable between a locked position in which said graspingportion is prevented from moving fore and aft and an unlocked positionin which said grasping portion is free for moving fore and aft; a collarcoupled to said housing and rotatable relative to said housing, saidcollar including threads; a valve assembly disposed in said housing,said valve assembly including a main valve moveable between an open-mainvalve position and a closed-main valve position and a pilot valvemoveable between an open-pilot valve position and a closed-pilot valveposition, said actuator operatively coupled to said valve assembly suchthat said pilot valve and said main valve are both moveable betweentheir respective said open and said closed positions in response tomovement of said grasping portion with said pilot valve reaching saidopen-pilot valve position before said main valve reaches said open-mainvalve position whereby said pilot valve reaches said open-pilot valveposition first to equalize pressure on both sides of said main valve andenable movement of said main valve to said open-main valve position; anda biasing device disposed in said housing and coupled to said valveassembly for biasing both said pilot valve and said main valve towardtheir respective said closed positions.
 2. A transfer device as setforth in claim 1 wherein said main valve defines an aperture forconveying a flow of fluid therethrough when said pilot valve is in saidopen-pilot valve position.
 3. A transfer device as set forth in claim 2wherein said pilot valve is coupled to said main valve and is at leastpartially disposed within said aperture and moveable within saidaperture during said movement of said actuator.
 4. A transfer device asset forth in claim 3 further including a retainer disposed in saidaperture for coupling said pilot valve to said main valve.
 5. A transferdevice as set forth in claim 4 wherein said pilot valve defines a travelpath receiving said retainer such that said retainer rides in saidtravel path prior to said pilot valve engaging said retainer duringmovement of said actuator.
 6. A transfer device as set forth in claim 5wherein said pilot valve includes an abutment defining one end of saidtravel path with said abutment spaced from said retainer when said pilotvalve is in said closed-pilot valve position and said abutment movingtoward said retainer when said pilot valve is moved toward saidopen-pilot valve position such that said abutment engages said retainerfor moving said main valve to said open-main valve position.
 7. Atransfer device as set forth in claim 2 further including a sealdisposed in said aperture for sealing between said pilot valve and saidmain valve to prevent the flow of fluid through said aperture when saidpilot valve is in said closed-pilot valve position.
 8. A transfer deviceas set forth in claim 1 wherein said pilot valve includes a body and ahead extending forward from said body.
 9. A transfer device as set forthin claim 8 wherein said aperture defines a first section having a firstdiameter and a second section having a smaller second diameter such thatsaid body of said pilot valve is at least partially disposed in saidfirst section of said aperture and said head of said pilot valve is atleast partially disposed in said second section of said aperture.
 10. Atransfer device as set forth in claim 9 wherein said aperture furtherdefines a third section having a third diameter smaller than said seconddiameter such that the flow of fluid passes through said third sectionto exit said aperture of said main valve.
 11. A transfer device fortransferring fluid, said device comprising: a housing defining an inlet,an outlet, and a longitudinal axis; an actuator pivotally coupled tosaid housing about a pivot axis transverse to said longitudinal axis,said actuator having a grasping portion moveable fore and aft relativeto said housing to pivot said actuator about said pivot axis; a collarcoupled to said housing and rotatable relative to said housing, saidcollar including threads; a valve assembly disposed in said housing,said valve assembly including a main valve moveable between an open-mainvalve position and a closed-main valve position and a pilot valvemoveable between an open-pilot valve position and a closed-pilot valveposition, said actuator operatively coupled to said valve assembly suchthat said pilot valve and said main valve are both moveable betweentheir respective said open and said closed positions in response tomovement of said grasping portion with said pilot valve reaching saidopen-pilot valve position before said main valve reaches said open-mainvalve position whereby said pilot valve reaches said open-pilot valveposition first to equalize pressure on both sides of said main valve andenable movement of said main valve to said open-main valve position; anda biasing device disposed in said housing and coupled to said pilotvalve for biasing said pilot valve toward said closed position.
 12. Atransfer device for transferring fluid, said device comprising: ahousing defining an inlet, an outlet, and a longitudinal axis; anactuator coupled to said housing and having a grasping portion moveablefore and aft relative to said housing to move said actuator; a collarcoupled to said housing and rotatable relative to said housing, saidcollar including threads; a valve assembly disposed in said housing,said valve assembly including a main valve moveable between an open-mainvalve position and a closed-main valve position and a pilot valvemoveable between an open-pilot valve position and a closed-pilot valveposition, said actuator operatively coupled to said valve assembly suchthat said pilot valve and said main valve are both moveable betweentheir respective said open and said closed positions in response tomovement of said grasping portion with said pilot valve reaching saidopen-pilot valve position before said main valve reaches said open-mainvalve position whereby said pilot valve reaches said open-pilot valveposition first to equalize pressure on both sides of said main valve andenable movement of said main valve to said open-main valve position; anda biasing device disposed in said housing and coupled to said pilotvalve for biasing said pilot valve toward said closed position.
 13. Atransfer device as set forth in claim 12 wherein said main valve definesan aperture for conveying a flow of fluid therethrough when said pilotvalve is in said open-pilot valve position.
 14. A transfer device as setforth in claim 13 further including a seal disposed in said aperture forsealing between said pilot valve and said main valve to prevent the flowof fluid through said aperture when said pilot valve is in saidclosed-pilot valve position.
 15. A transfer device as set forth in claim13 further including a retainer coupling said pilot valve to said mainvalve wherein said pilot valve is at least partially disposed withinsaid aperture and moveable within said aperture during said movement ofsaid actuator with said retainer limiting movement of said pilot valvein said aperture.
 16. A transfer device as set forth in claim 12 furtherincluding a lock operatively coupled to said actuator and movablebetween a locked position in which said grasping portion is preventedfrom moving fore and aft and an unlocked position in which said graspingportion is free for moving fore and aft.